Features: It is especially designed for Samsung Galaxy S3. Ultra-thin design compact and light weight without increasing additional weight of the S3. Adding wireless charging feature by piggybacking it on the battery of S3 it works well with any Qi-enabled charger. Easy to use. The receiver can be attached to the the battery all the time and it would not interrupt the normal use of the S3. Specifications: Color: Black Input power: WPC 5W Output: 1000mA Charging current: DC5V/500mA (Max) Charging time: about 5 hrs Reaction temperature: -10 ~ 40'C Working heat up range: below 20'C (ambient temperature below 25'C) Working ambient humidity: below 80% Working life: Charge & discharge above 4000 times Size: Approx. 61.5 * 49.3 * 1mm / 2.4 * 1.9 * 0.04in Weight: 5g / 0.17oz How to use it : Step 1: Open the back cover of the Samsung Galaxy S3; Step 2: Stick the receiver card to the mobile phone's battery and the two protuberant touch points must touch the two recesses next to the battery; Step 3: Close the back cover; Step 4: Place the mobile phone onto the Qi wireless charging pad (not included).